I need a education on trailer brakes

[Magard]

This older Great Dane trailer I bought has super grabby brakes. All adjusted right. No leaking oil seals, newer looking shoes. I changed the glad hands out to 1/2 inch quick couplers. Nothing I haven’t done in the past. This trailer had a goofy valve on the blue side. Like a check valve release valve or something. This trailer grabs quick and releases fine. I’m not sure what is up I’ve never seen one like this. Does the air valve on the trailer air supply have a spring in it that pushes back against application pressure or something.

[arch_stanton]

check the application pressure at the chamber you will need a tee fitting and a gauge and someone to apply brakes and another to check the pressure on the gauge is the same at chamber and in the truck, test for crack pressure should be 5 psi or less then test for readings at 10 psi 20,30 if everything is even then its in the shoes or install issues

[Brock]

If you normally back the brakes off half a turn, back them off 3/4 of a turn, still well within spec.

[Mattman]

The goofy blue glad hand is made like that to help get the air off the service brakes faster when you let you on the brake pedal.

How much have you used this trailer? Brakes are usually grappy if they have been sitting for awhile.

[Magard]

That’s what I thought on the goofy glad hand. It’s been pulled about 2500 miles now. The more I think about it. It must be something in the valve on the air tank on the trailer. Like a regulator valve. Application pressure must be adding up to more pressure out of the tank.

[Mattman]

Swap the valve on the trailer and see what happens. Shop at work replaces brake valves regular.

[Lonestar10]

Your truck should have an application gauge I rarely get over 20psi on mine unless I'm in a hurry to stop

[Magard]

https://youtu.be/f3LD8M0HKjo

The spring in this relay valve is what I’m talking about. Maybe being weak.

[Casper]

(01-19-2020 )Magard Wrote:  This older Great Dane trailer I bought has super grabby brakes. All adjusted right. No leaking oil seals, newer looking shoes. I changed the glad hands out to 1/2 inch quick couplers. Nothing I haven’t done in the past. This trailer had a goofy valve on the blue side. Like a check valve release valve or something. This trailer grabs quick and releases fine. I’m not sure what is up I’ve never seen one like this. Does the air valve on the trailer air supply have a spring in it that pushes back against application pressure or something.

Can you share what year the trailer is?